Paperless is great. But it does not highlight the search text. The android app paperless mobile does.
Another option could be zotero. It is meant for sientific papers but very powerful in handling large PDF collections. Hard to completly selfhost. But using WebDAV as storage is straightforward. Good look, let us know where you land.
I do Greek goods and Titans which leads to a similar problem. But I just love that my main proxmox host is namend after a Titan with many arms.